Pulmonary vein narrowing after visually guided laser balloon ablation: Occurrence and clinical correlates

Comprehensive review of pulmonary vein stenosis post-atrial fibrillation ablation: diagnosis, management, and prognosis

Pulmonary vein stenosis (PVS) can occasionally occur in the follow-up after pulmonary vein isolation (PVI) for atrial fibrillation (AF). During PVI, ablation is performed at the PV ostium or distal part, leading to tissue damage. This damage can result in fibrosis of the necrotic myocardium, proliferation, and thickening of the vascular intima, as well as thrombus formation, further advancing PVS. Mild-to-moderate PVS often remains asymptomatic, but severe PVS can cause symptoms, such as dyspnea, cough, fatigue, decreased exercise tolerance, chest pain, and hemoptysis. These symptoms are due to pulmonary hypertension and pulmonary infarction. Imaging evaluations such as contrast-enhanced computed tomography are essential for diagnosing PVS. Early suspicion and detection are necessary, as underdiagnosis can lead to inappropriate treatment, disease progression, and poor outcomes. The long-term prognosis of PVS remains unclear, particularly regarding the impact of mild-to-moderate PVS over time. PVS treatment focuses on symptom management, with no established definitive solutions. For severe PVS, transcatheter PV angioplasty is performed, though the risk of restenosis remains high. Restenosis and reintervention rates have improved with stent implantation compared with balloon angioplasty. The role of subsequent antiplatelet therapy remains uncertain. Dedicated evaluation is essential for accurate diagnosis and appropriate management to avoid significant long-term impacts on patient outcomes.

Pulmonary Vein Stenosis After Catheter Ablation of Atrial Fibrillation Using a Cryoballoon, Hot Balloon, or Laser Balloon

BACKGROUND

Pulmonary vein stenosis (PVS) after PV isolation (PVI) for atrial fibrillation (AF) is a severe complication that requires angioplasty. This study aimed to compare the reduction of the cross-sectional PV area (PVA) and the incidence of PVS after cryoballoon (CB)-PVI, hot balloon (HB)-PVI, or laser balloon (LB)-PVI.

METHODS AND RESULTS

A total of 320 patients who underwent an initial catheter ablation procedure for AF using a CB, HB, or LB in 2 hospitals were included. They underwent contrast-enhanced multidetector CT before and 3 months after the procedure. In all 4 PVs, the reduction in PVA was more significant in the LB group than in the CB or HB groups, respectively. Moderate (50-75%) and severe (>75%) PVS were observed in 5.3% and 0.5% of the PVs, respectively. Although moderate PVS was more frequently observed in the LB group than in the CB or HB groups (8.2%, 3.8%, and 5.0%; P=0.03), the incidence of severe PVS was similar in the LB, CB, and HB groups (0.3%, 0.5%, and 1.0%; P=0.46). Symptomatic PVS requiring intervention occurred in 1 (0.3%) patient.

CONCLUSIONS

Although the reduction in cross-sectional PVA and the incidence of moderate PVS after LB-PVI was more significant than after CB-PVI or HB-PVI, it rarely led to severe PVS. Symptomatic PVS requiring intervention was rare after the balloon ablation of AF.

Evaluation of linear lesion formation and thermodynamics by dragging ablation with the third-generation laser balloon

Background

The lesion formation properties of a motorized rotational delivery (RAPID) mode, third-generation laser balloon (LB3) ablation compared to point-by-point laser ablation in patients with atrial fibrillation remain unclear.

Objective

The purpose of this study was to assess lesion characteristics and thermodynamics in LB3 ablation with a RAPID mode in vitro model.

Methods

Chicken muscles were cauterized using LB3 in RAPID mode with 13 W and 15 W and 50% overlapped point-by-point fashion with 7 W/30 seconds, 8.5 W/20 seconds, 10 W/20 seconds, and 12 W/20 seconds. Lesion depth, width, and continuity were compared. Lesion continuity was classified by the visible gap degree categorized from 1 (perfect) to 3 (poor). Thermodynamics and maximum tissue temperatures were assessed under infrared thermographic monitoring. Fifteen and 5 lesions were evaluated per ablation protocol for measurement of lesion size and continuity and for thermographic assessment, respectively.

Results

Lesion depth and width were smaller in RAPID mode laser ablation than point-by-point laser ablation (P <.001). However, RAPID mode laser ablation revealed sufficient mean lesion depth of 5 mm or more. Lesion continuity was 1 (perfect) in all samples in RAPID mode laser ablation and point-by-point laser ablation (P = 1). Infrared thermographic observation demonstrated fast and gapless linear lesion formation with thermal stacking in RAPID mode laser ablation. Maximum tissue temperature was lower in RAPID mode laser ablation than point-by-point laser ablation (P <.001).

Conclusion

RAPID mode LB3 ablation could provide fast, gapless, and acceptable lesion formation with thermal stacking and moderate tissue temperature rise.

Laser balloon in pulmonary vein isolation for atrial fibrillation: current status and future prospects

INTRODUCTION

Visually guided laser balloon (LB) catheter has been an established modality dedicated for pulmonary vein (PV) isolation in patients with atrial fibrillation. The newly updated version of this novel device has technically evolved recent years.

AREAS COVERED

This review will summarize the contemporary technical evolution of LB catheter. Available efficacy outcomes and the historical change of ablation style will be evaluated. Furthermore, the future perspectives for clinical practice are discussed.

EXPERT COMMENTARY

The initial LB ablation system provided comparable clinical results in PV isolation with other technologies, but with a unique strategical concept enabling the direct visualization of the tissue to cauterize. With multigenerational development, the LB catheter has been equipped with more compliant balloon for favorable PV occlusion and a robotically motor driven continuous ablation mode (RAPID mode). These technical innovations changed the concept of the ablation strategy using LB catheter as 'point-by-point' into 'single-shot' fashion. The remaining tasks are further improvements such as equipping with real-time recording system of intracardiac electrogram, durable structured balloon and the instrument for visualizing the cauterization area in a 360-degree panoramic view, which includes potential possibilities to develop this novel device to the more optimal device for PV isolation.

Validation of lesion durability following pulmonary vein isolation using the new third-generation laser balloon catheter in patients with recurrent atrial fibrillation

BACKGROUND

The second- and third-generation endoscopic ablation systems (EAS2 and EAS3) have been launched in recent years. We aimed to assess the lesion durability as well as gap localization using the multigenerational novel technologies in patients with recurrent atrial fibrillation (AF).

METHODS

Consecutive patients who underwent second ablation for recurrent AF following the initial pulmonary vein isolation (PVI) with EAS2 or EAS3 were retrospectively investigated. The persistent durability of PVI, gap localization at the second procedure, and procedural/anatomical features of durable PVI were analyzed.

RESULTS

Among 225 patients treated with EAS3 (N = 125) and EAS2 (N = 100), 34 patients (EAS3: 13 patients, 50 PVs, EAS2: 21 patients, 82 PVs) underwent a second procedure because of recurrent AF mean 11.9 ± 9.3 months after the initial procedure. Persistent isolation of all four PVs was recorded in 6 (46.2%) patients in EAS3 group and 4 (19.1%) patients in EAS2 group (p = 0.130). Ninety-one out of 132 (68.9%) PVs were persistently isolated with a higher rate in EAS3 group (82.0% vs. EAS2 group: 61.0%, p = 0.0113). A total of 45 gaps were recorded in 41 PVs. Right superior PV (RSPV) was the predominantly common reconnected vein (15 gaps, 14 PVs) irrespective of generations (EAS3: 4 gaps in 3 PVs and EAS2: 12 gaps in 11 PVs). Logistic multivariate regression analysis revealed ablation without reduced energy dose (5.5-7 W) as an independent predictor of durable PVI [adjusted OR: 3.70, 95% CI (1.408-10.003)], p = 0.008].

CONCLUSION

The technical innovation resulted in a higher lesion durability in EAS3-guided PVI in patients with recurrent AF. The most common gap location was found at RSPV in successor EASs. Ablation without reduced energy was a predictor of durable PVI in successor EASs.